Bi-Temporal Analysis of Landscape Changes in the Easternmost Mediterranean Deltas Using Binary and Classified Change Information

The aim of this study is (1) to quantify landscape changes in the easternmost Mediterranean deltas using bi-temporal binary change detection approach and (2) to analyze relationships between conservation/management designations and various categories of change that indicate type, degree and severity of human impact. For this purpose, image differencing and ratioing were applied to Landsat TM images of 1984 and 2006. A total of 136 candidate change images including normalized difference vegetation index (NDVI) and principal component analysis (PCA) difference images were tested to understand performance of bi-temporal pre-classification analysis procedures in the Mediterranean delta ecosystems. Results showed that visible image algebra provided high accuracies than did NDVI and PCA differencing. On the other hand, Band 5 differencing had one of the lowest change detection performances. Seven superclasses of change were identified using from/to change categories between the earlier and later dates. These classes were used to understand spatial character of anthropogenic impacts in the study area and derive qualitative and quantitative change information within and outside of the conservation/management areas. Change analysis indicated that natural site and wildlife reserve designations fell short of protecting sand dunes from agricultural expansion in the west. East of the study area, however, was exposed to least human impact owing to the fact that nature conservation status kept human interference at a minimum. Implications of these changes were discussed and solutions were proposed to deal with management problems leading to environmental change.     

Short-term changes in mobile dunes at Port Alfred,South Africa

Development along the western beachfront of Port Alfred, which is situated along a sandy shoreline, increased markedly in the 1960s as the coastal town became a popular holiday resort. This development included the removal of coastal vegetation, which resulted in the destabilization of dunes and migration of sand westerly onto the road, West Beach parking lot, and lawns of the cabanas. Sand traps were constructed to collect sand blowing across the dunes over set periods, and the net sand movement along the mobile dune belt was calculated using Hunter's equation. The dunes show an easterly movement of sand at a rate of 3.5 m/yr, which is comparable with figures recorded along other areas of this coastline. Considering the wind regime and amount of sand movement along this coast, it is inappropriate to clear vegetation and develop within the dune region.     

Sand Fences in the Coastal Zone: Intended and Unintended Effects

Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.     

An environmental perspective of the post-tsunami scenario along the coast of Tamil Nadu, India: role of sand dunes and forests

An endeavor to feel the pulse of a coast devastated by a powerful oceanographic event is made. Results of field investigations along Tamil Nadu seaside revealed that the tsunami of December 2004 demolished dwellings within strips ranging from 6 to 132m (average width, 41m) from the dune, and flooded up to 862m (average, 247m) from the shore. The event damaged sand dunes, ripped dune vegetation, created new water bodies and shattered high value assets. Comparatively, casuarina forests performed remarkably. Uprooting of trees was exclusively restricted to a frontal strip ranging from 5 to 25m (average width, 14m) nearest to the shore where the maximum wave run-up was 6.5m above sea level. Sand dunes in general, and casuarina forests in particular, posses an innate capacity to dissipate powerful waves. This inference is supported by (a) negligible over wash along belts characterized by high dune complexes, (b) intact villages shielded by dense forests as well as sand dunes, and (c) maximum destruction of open beach front influenced by intense human activity. In this context, the coastal regulation zone (CRZ) Notification of 1991 offers sufficient scientific validity to be endorsed. However, post-tsunami ecosystem management initiatives lack a scientific basis. Therefore, a coastal hazards policy, that considers adaptation, dune restoration and forested buffer zones, is a sustainable long-term option for Indian coasts.     

Applying the principle of sustainability to coastal sand mining: The case of Pakiri-Mangawhai Beach,New Zealand

The purpose of New Zealand's Resource Management Act (1991) is to promote the sustainable management of natural and physical resources. Coastal sand mining may be consistent with this purpose where: (1) extractions occur from sediment systems open to inputs of sediment, and the volumes extracted do not limit the natural development, physical characteristics, and ecological diversity of the coastal environments affected; or (2) extractions from palimpsest or relict sedimentary deposits occur at a rate where the rate of extraction is insignificant compared with the volume of the resource. The response of coastal sand mining companies and consent-granting authorities to the requirements of the Resource Management Act (1991) are examined with respect to recent applications to mine sand from a coastal sand body in the Hauraki Gulf, New Zealand. The assessments of environmental effects (AEE) submitted in support of these applications do not establish the sustainability of the sand mining operations. Specifically they do not define the dimensions of the active sediment system, quantify the volume of the related resource, or state the period within which sustainability is achievable. Further, the AEE do not consider the cumulative effects of the extractions, either in terms of the total volume of sand mined or the cumulative effects of different anthropogenic activities. The test of sustainability demands a quality of information and understanding of coastal systems that is well beyond that obtained in the past or accepted at present. There is a clear need for New Zealand's resource management legislation to be supplemented by technical guidelines that help ensure the test of sustainability is rigorously applied.     

长庆气田——呼和浩特输气管道工程生态环境保护及恢复对策

针对管道工程的特点,尤其是管道工程穿越脆弱沙地生态系统的特点,在分析管道沿线生态环境现状及特点的基础上,重点从沙地生态系统的演替规律出发,分析了管道工程沙地段的主要环境问题,借鉴当地已有的生态恢复的成功经验,进一步提出了穿越脆弱沙地生态系统管道工程项目的生态保护和恢复对策。     

Effects of Trampling Limitation on Coastal Dune Plant Communities

Sandy coastlines are sensitive ecosystems where human activities can have considerable negative impacts. In particular, trampling by beach visitors is a disturbance that affects dune vegetation both at the species and community level. In this study we assess the effects of the limitation of human trampling on dune vegetation in a coastal protected area of Central Italy. We compare plant species diversity in two recently fenced sectors with that of an unfenced area (and therefore subject to human trampling) using rarefaction curves and a diversity/dominance approach during a two year study period. Our results indicate that limiting human trampling seems to be a key factor in driving changes in the plant diversity of dune systems. In 2007 the regression lines of species abundance as a function of rank showed steep slopes and high Y-intercept values in all sectors, indicating a comparable level of stress and dominance across the entire study site. On the contrary, in 2009 the regression lines of the two fenced sectors clearly diverge from that of the open sector, showing less steep slopes. This change in the slopes of the tendency lines, evidenced by the diversity/dominance diagrams and related to an increase in species diversity, suggests the recovery of plant communities in the two fences between 2007 and 2009. In general, plant communities subject to trampling tended to be poorer in species and less structured, since only dominant and tolerant plant species persisted. Furthermore, limiting trampling appears to have produced positive changes in the dune vegetation assemblage after a period of only two years. These results are encouraging for the management of coastal dune systems. They highlight how a simple and cost-effective management strategy, based on passive recovery conservation measures (i.e., fence building), can be a quick (1–2 years) and effective method for improving and safeguarding the diversity of dune plant communities.     

Monitoring Environmental Changes in the Mediterranean Coastal Landscape: The Case of Cukurova, Turkey

This paper describes a remote sensing approach used to monitor temporal land use/cover (LULC) changes in Cukurova, an extensive coastal plain in the southeast Mediterranean coast of Turkey. The area has varied terrain ranging from low-lying alluvial deposits to rocky hills and mountains characterized by limestone outcrops. The ecological and economic importance of the area can be attributed to the existence of important coastal ecosystems (e.g., wetlands and sand dunes) and a wide range of industries located along the eastern coast. Temporal changes in the coastal landscape between 1984 and 2000 were evaluated using digital interpretation of remotely sensed satellite data. Pairwise comparison methods were used to quantify changes from 1984 to 1993 and 1993 to 2000 using multitemporal Landsat TM and ETM+ images, acquired in 1984, 1993, and 2000, respectively. Total change area was 2448 ha from 1984 to 1993 and increased more than twofold, to 6072 ha from 1993 to 2000. Change trends were determined using the information provided from individual change detection outputs of different periods. The most prominent changes were estimated to have occurred in agriculture, urban, and natural vegetation cover. Agriculture has increasingly grown over marginal areas, whereas urban development occurred at the expense of prime croplands across both time steps.     

Recovery in Naturally Dynamic Environments: A Case Study from the Sperrgebiet,Southern African Arid Succulent Karoo

Little is known about the process of vegetation recovery and associated time frames in the Succulent Karoo Biome of southern Africa. This study investigated the recovery of vegetation on sites impacted by mining (different types of dumps and mined areas) in the arid succulent karoo. The main aim of this study was to determine the state of recovery, time frames, successional stages, and the influence of environmental factors on recovery of coastal dune and sand plain plant communities. For this purpose, vegetation was recorded on some 121 sites throughout a coastal strip of approximately 100 × 3 km in Namibia’s restricted diamond area (Sperrgebiet). Using the species pool concept to derive vegetation reference sites and dominance-diversity curves, recovery of vegetation (measured in terms of species richness and cover) in these altered landscapes reached about 46% on the oldest, 51-year-old mine dumps. However, based on species richness, richness levels similar to the undisturbed reference sites were recorded after 30 years, following a logarithmic trend. Successional stages of natural recovery were indicated in this dynamic coastal environment and Cladoraphis cyperoides and Galenia fruticosa appear to be early successional species. Scaling up of studies to landscape level and developing a target community using the species pool concept are discussed as means to measure recovery in dynamic biological communities. On these altered, man-made landforms, the availability of seed may be the bottleneck to achieve vegetation cover comparable to undisturbed vegetation in the surrounding. Hence, restoration efforts should focus on this aspect.     

THE VULNERABILITY OF WETLANDS TO CLIMATE CHANGE: A HYDROLOGIC LANDSCAPE PERSPECTIVE1

ABSTRACT: The vulnerability of wetlands to changes in climate depends on their position within hydrologic landscapes. Hydrologic landscapes are defined by the flow characteristics of ground water and surface water and by the interaction of atmospheric water, surface water, and ground water for any given locality or region. Six general hydrologic landscapes are defined; mountainous, plateau and high plain, broad basins of interior drainage, riverine, flat coastal, and hummocky glacial and dune. Assessment of these landscapes indicate that the vulnerability of all wetlands to climate change fall between two extremes: those dependent primarily on precipitation for their water supply are highly vulnerable, and those dependent primarily on discharge from regional ground water flow systems are the least vulnerable, because of the great buffering capacity of large ground water flow systems to climate change.     

Morphological changes at Vellar estuary, India--impact of the December 2004 tsunami

Coastal subsystems formed by interaction of various processes, impacted by natural hazards like tsunami and storms, pose irreversible morphological changes. Vellar estuary, located on the southeast coast of India, with huge sand dunes (of 3-6m height and spread to 560ha) and barrier islands, has undergone extensive morphological changes due to the giant Indian Ocean tsunami that occurred on 26th December 2004. The damage caused by the tsunami has been quantified using extensive field data collected during pre- and post-tsunami periods through Real Time Kinematic GPS (for mapping coastal features and beach profiles) and Geographic Information System (GIS) couple. The tsunami with a wave height as high as 4m not only inundated the entire coastal land up to a maximum of 2km but also eroded the sand dunes and deposited the eroded material at the inlet, which ultimately formed as a vast tidal flat spread over 31ha. The estuary has suffered immensely due to the tsunami especially in terms of (i) loss of natural protection barriers (sand dunes), which made this coastal area more vulnerable to storm attack, and (ii) shallowness of inlet creating hindrance to navigation of fishing vessels. Based on the observations made at Vellar coast and past recovery experiences of tsunami/hurricanes elsewhere in the world, we contend that the morphological loss might take at least two annual cycles to regain its original form and the rebuilding of sand dunes may even take a decade.     

Soil Fertility, Salinity and Nematode Diversity Influenced by Tamarix ramosissima in Different Habitats in an Arid Desert Oasis

The aim of this paper was to assess the influence of tamarisk shrubs on soil fertility, salinity and nematode communities in various habitats located in an arid desert-oasis region in northwest China. Three habitats were studied: sand dune, riparian zone and saline meadow, where tamarisk shrubs have been established in recent decades in order to vegetation restoration used as desertification control and saline land rehabilitation projects and become the dominant plant community. The parameters measured include soil organic carbon (SOC), total nitrogen, available phosphorus (P) and potassium (K), pH, salt component, and nematode community characteristics. Enrichment ratios (a comparison of the soil measurements between soils under canopy and in the open interspaces) for soil nutrients and salinity were used to evaluate fertility and salinity islands underneath the tamarisk shrubs. The soil nematode community was used as a biological indicator of soil condition. SOC and available P and K were higher beneath the plant canopy than in the open interspaces outside that canopy. The enrichment ratios for SOC and nutrients were highest for the sand dune habitat and tamarisk shrubs clearly created islands of greater salinity under the canopies. Nematode abundance per 100 g dry soil varied considerably between the locations and habitats, with the highest abundance found in sand dune and the lowest in saline meadow. A significantly higher nematode abundance and a lower trophic diversity were found in soils under the canopy compared to the soils in the open interspaces. With the exception of saline meadow, the abundance of bacterivores increased and fungivores decreased under the canopy relative to the open interspaces, and bacterivores dominated under the canopies in the sand dune and riparian habitats. The enrichment ratios for salinity were higher than for fertility, suggesting that improved soil fertility can not limit the impact of salinization beneath tamarisk shrubs. The adverse effect of salt accumulation on the soil environment should be taken into account when using tamarisk as restoration plant species, especially in saline meadow and controlling of tamarisk density should be considered when undertaking re-vegetation projects in the arid desert oasis regions.     

Efficient management of marine resources in conflict: An empirical study of marine sand mining, Korea

This article develops a dynamic model of efficient use of exhaustible marine sand resources in the context of marine mining externalities. The classical Hotelling extraction model is applied to sand mining in Ongjin, Korea and extended to include the estimated marginal external costs that mining imposes on marine fisheries. The socially efficient sand extraction plan is compared with the extraction paths suggested by scientific research. If marginal environmental costs are correctly estimated, the developed efficient extraction plan considering the resource rent may increase the social welfare and reduce the conflicts among the marine sand resource users. The empirical results are interpreted with an emphasis on guidelines for coastal resource management policy.     

Drivers of Coastal Shoreline Change: Case Study of Hon Dat Coast,Kien Giang,Vietnam

Coastal shorelines are naturally dynamic, shifting in response to coastal geomorphological processes. Globally, land use change associated with coastal urban development and growing human population pressures is accelerating coastal shoreline change. In southern Vietnam, coastal erosion currently is posing considerable risks to shoreline land use and coastal inhabitants. The aim of this paper is to quantify historical shoreline changes along the Hon Dat coast between 1995 and 2009, and to document the relationships between coastal mangrove composition, width and density, and rates of shoreline change. The generalized linear mixed-effects models were used to quantify the major biophysical and land-use factors influencing shoreline change rates. Most significant drivers of the rates of change are cutting of mangroves, the dominant mangrove genus, changes in adjacent shoreline land use, changes of shoreline land cover, and width of fringing mangroves. We suggest that a possible and inexpensive strategy for robust mangrove shoreline defense is direct mangrove planting to promote mangrove density with the presence of breakwater structures. In the shorter term, construction of coastal barriers such as fence-structured melaleuca poles in combination with mangrove restoration schemes could help retain coastal sediments and increase the elevation of the accretion zone, thereby helping to stabilize eroding fringe shorelines. It also is recommended that implementation of a system of payments for mangrove ecosystem services and the stronger regulation of mangrove cutting and unsustainable land-use change to strengthen the effectiveness of mangrove conservation programs and coastal land-use management.     

Predicting flooding probability for beach/dune systems

The determination of the risk from flooding that shorefront communities face is an important component of coastal management that has not been resolved successfully. Wave runup offers one way of quantifying the risk of coastal flooding that results from overtopping by storm waves. The calculation of runup probabilities uses wave frequency analysis and an average beach/dune profile for a given shoreline segment. The amount of risk is determined by using a runup probability curve for specific shoreline locations within the segment. The procedure is demonstrated using the New Jersey shoreline as an example, and results indicate a higher degree of risk in the southern part of the state. Although the procedure is attractive, there is a need for additional field research to test: (1) the accuracy of the calculation procedure; (2) the applicability of a design profile for a shoreline segment; and (3) whether a non-storm beach/dune profile may be used in the calculation. In terms of the broader subject of coastal hazards, these runup calculations need to be integrated with research on beach erosion to provide a comprehensive assessment of the risk at specific locations.     

Land use change effects on forest carbon cycling throughout the southern United States

We modeled the effects of afforestation and deforestation on carbon cycling in forest floor and soil from 1900 to 2050 throughout 13 states in the southern United States. The model uses historical data on gross (two-way) transitions between forest, pasture, plowed agriculture, and urban lands along with equations describing changes in carbon over many decades for each type of land use change. Use of gross rather than net land use transition data is important because afforestation causes a gradual gain in carbon stocks for many decades, while deforestation causes a much more rapid loss in carbon stocks. In the South-Central region (Texas to Kentucky) land use changes caused a net emission of carbon before the 1980s, followed by a net sequestration of carbon subsequently. In the Southeast region (Florida to Virginia), there was net emission of carbon until the 1940s, again followed by net sequestration of carbon. These results could improve greenhouse gas inventories produced to meet reporting requirements under the United Nations Framework Convention on Climate Change. Specifically, from 1990 to 2004 for the entire 13-state study area, afforestation caused sequestration of 88 Tg C, and deforestation caused emission of 49 Tg C. However, the net effect of land use change on carbon stocks in soil and forest floor from 1990 to 2004 was about sixfold smaller than the net change in carbon stocks in trees on all forestland. Thus land use change effects and forest carbon cycling during this period are dominated by changes in tree carbon stocks.     

Changes in Microbial Community Structure and Soil Biological Properties in Mined Dune Areas During Re-vegetation

The aim of this study was to describe the impact of re-vegetation on the restoration of microbial community structure and soil microbiological properties in sand dunes that had been affected by mining activity. Soil samples were collected during the dry and rainy seasons from a chronosequence (1, 9, 21 years) of re-vegetated dunes using a single preserved dune as a reference. The composition of the fatty acid methyl esters and soil microbial properties were evaluated. The results showed that the changes in microbial community structure were related to seasonal variations: biomarkers of Gram-positive bacteria were higher than Gram-negative bacteria during the dry season, showing that this group of organisms is more tolerant to these stressful conditions. The microbial community structure in the natural dune was less affected by seasonal variation compared to the re-vegetated areas, whereas the opposite was observed for microbiological properties. Thus, in general, the proportion of saprobic fungi was higher in the natural dune, whereas Gram-negative bacteria were proportionally more common in the younger areas. Although over time the re-vegetation allows the recovery of the microbial community and the soil functions, these communities and functions are different from those found in the undisturbed areas.     

Scenario-based stakeholder engagement: incorporating stakeholders preferences into coastal planning for climate change

Climate change poses many challenges for ecosystem and resource management. In particular, coastal planners are struggling to find ways to prepare for the potential impacts of future climate change while dealing with immediate pressures. Decisions on how to respond to future risks are complicated by the long time horizons and the uncertainty associated with the distribution of impacts. Existing coastal zone management approaches in the UK either do not adequately incorporate changing stakeholder preferences, or effectively ensure that stakeholders are aware of the trade-offs inherent in any coastal management decision. Using a novel method, scenario-based stakeholder engagement, which brings together stakeholder analysis, climate change management scenarios and deliberative techniques, the necessary trade-offs associated with long term coastal planning are explored. The method is applied to two case studies of coastal planning in Christchurch Bay on the south coast of England and the Orkney Islands off the north coast of Scotland. A range of conflicting preferences exist on the ideal governance structure to manage the coast under different climate change scenarios. In addition, the results show that public understanding of the trade-offs that have to be made is critical in gaining some degree of public support for long term coastal decision-making. We conclude that scenario-based stakeholder engagement is a useful tool to facilitate coastal management planning that takes into account the complexities and challenges of climate change, and could be used in conjunction with existing approaches such as the Shoreline Management Planning process.     

The Fate of Priority Areas for Conservation in Protected Areas: A Fine-Scale Markov Chain Approach

Park managers in alpine areas must deal with the increase in forest coverage that has been observed in most European mountain areas, where traditional farming and agricultural practices have been abandoned. The aim of this study is to develop a fine-scale model of a broad area to support the managers of Paneveggio Nature Park (Italy) in conservation planning by focusing on the fate of priority areas for conservation in the next 50–100 years. GIS analyses were performed to assess the afforestation dynamic over time using two historical maps (from 1859 and 1936) and a series of aerial photographs and ortho-photos (taken from 1954 to 2006) covering a time span of 150 years. The results show an increase in the forest surface area of about 35%. Additionally, the forest became progressively more compact and less fragmented, with a consequent loss of ecotones and open habitats that are important for biodiversity. Markov chain-cellular automata models were used to project future changes, evaluating the effects on a habitat scale. Simulations show that some habitats defined as priority by the EU Habitat Directive will be compromised by the forest expansion by 2050 and suffer a consistent loss by 2100. This protocol, applied to other areas, can be used for designing long-term management measures with a focus on habitats where conservation status is at risk.     

“湛茂阳”区域滨海旅游多维生态位及竞合发展策略研究

构建湛江、茂名、阳江3市和谐的滨海旅游竞合关系是粤西滨海旅游协同一体化高质量发展的重要内涵与实现途径。基于2012—2017年“湛茂阳”区域滨海旅游相关统计数据,构建了滨海旅游生态位测评指标体系,运用旅游生态位理论模型综合测评了“湛茂阳”区域滨海旅游生态位宽度、扩充度和重叠度,深入分析了“湛茂阳”区域滨海旅游产业综合竞争力、竞争态势与竞争程度。结果发现:①“湛茂阳”区域滨海旅游生态位宽度呈现“水平低、均衡化”的结构特征,3市滨海旅游产业综合竞争力与影响力弱,旅游综合竞争力从大到小的排序依次为湛江、茂名、阳江。②“湛茂阳”3市滨海旅游综合生态位扩充态势不明显,扩充度水平整体呈现均质化特征,局部存在一定程度的分异。③“湛茂阳”区域滨海旅游生态位重叠度高,旅游竞争激烈,旅游协同合作发展水平与效应较低。最后,从区域滨海旅游生态位的协同、错位、扩充3个视角科学提出了“湛茂阳”区域滨海旅游竞合发展策略。